A Quantitative Analysis of Toughening Mechanisms in Steel Fibre Reinforced Ultra-High-Performance Concrete Through Multimodal Nondestructive Evaluation

Published: 2019

Author(s):
Loshkov, D.
Peng, Y.
Kravchuk, R.
Landis, E. N.

Publication Name: 10th International Conference on Fracture Mechanics of Concrete and Concrete Structures

Publication URL: https://www.researchgate.net/publication/333859741_A_quantitative_analysis_of_toughening_mechanisms_in_steel_fibre_reinforced_ultra-high-performance_concrete_through_multimodal_nondestructive_evaluation

Research Area:
Keywords:
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Abstract:

For the joint purposes of better informed meso-scale models and for more rational for “ma-terials by design” concepts, we seek to isolate and measure the different mechanisms that lead to highstrength and high ductility of steel ?ber reinforced ultra-high-performance concrete (UHPC). Thework described here jointly applies quantitative x-ray computed tomography(CT) and acoustic emis-sion (AE) techniques to monitor and measure damage progression in split cylinder tests of UHPC.50-mm diameter specimens of two different ?ber types were CT scanned both before and after loadtesting. From the resulting images, ?ber alignment was evaluated to quantify its effect on specimenperformance. Results demonstrate the signi?cance of ?ber alignment, with best case being between20 and 30% higher than the worst case. Cumulative AE energy was also affected commensurately.Post-test CT scans of the specimen were used to measure internal energy dissipation due to both ma-trix cracking and ?ber pullout using calibration measurements for each. AE data, processed using anarti?cial neural network, was also used to classify energy dissipation. CT analysis showed that ?berpullout was the dominant energy dissipation mechanism, however, the sum of internal energy dissi-pation measured amounted to only 60% of the total energy dissipated by the specimens as measuredby the net work of load. AE analysis showed a more balanced distribution of energy dissipation. AEdata additionally showed how the dissipation mechanisms shift as damage accumulates.